Evidence for the involvement of endothelial cell products in adrenal CITED2 expression

The adrenal gland contains a well-organized network of blood vessels, and adrenocortical cells are situated in close proximity to endothelial cells. Recently, several new mechanisms have been characterized that control the release of aldosterone by adrenocortical cells, including the involvement of endothelial-cell-derived factors. Interestingly, a CBP/p300-interacting transactivator with ED-rich tail 2 (CITED2), which is necessary for adrenal development, has been linked to aldosterone synthesis. We have therefore examined the effects of endothelial-cell-conditioned medium (ECCM), as produced during the incubation of human umbilical vein endothelial cells for 24 h, on the promoter activity and mRNA and protein expression of CITED2 in adrenocortical cells as represented by the NCI-H295R cell line. We have found a dose-dependent effect of ECCM on CITED2 promoter activity; this peaks at 480%. Activation of the CITED2 promoter occurs in parallel to an increase in CITED2 messenger RNA (as quantified by real-time polymerase chain reaction) and protein. The stimulatory effect of ECCM can be reversed by blocking mitogen-activated protein kinase activity with the MEK1-inhibitor PD98059. We conclude that products secreted by endothelial cells control not only steroidogenesis, but also factors that are important for adrenocortical development, thereby highlighting the role of cellular interactions within adrenocortical development and physiology. This work was supported by a grant from the Doktor Robert Pfleger-Stiftung, Bamberg, Germany, to H.S.W.     

N30 + 10: global civil society,a decade after the battle of Seattle

Critical discussions among some in Palestinian studies describe foreign involvement in NGO development in the Occupied Territories since the 1990s as having been detrimental to Palestinian collective aspirations, and even a tool of imperialism. In the 1970s and 1980s, Palestinians in the West Bank and Gaza Strip mobilized their own civilian organizations to build an infrastructure of resistance to the Israeli Occupation that gave birth to the Intifada Uprising in December 1987. Foreign governments and organizations were drawn to their struggle and in the 1990s billions of dollars of foreign aid from more than 40 nations and over two dozen multilateral organizations flowed through hundreds of local and foreign NGOs. But this investment in the “peace process” did not stop a worsening occupation, and a second al Aqsa Intifada began in the fall 2000. Palestinian civil society suffered crippling blows and foreign actors were reduced to disaster relief and harm reduction. This article presents three ethnographic portraits from 1992, 1995 and 2002, that examine these changes in Palestinian civil society and the scholarly criticisms of foreign involvement. This article argues that such involvement could put Palestinian participants in a dangerous in-between social position, but that these positions of contradiction are often preferable to the destruction of militarism.     

Amino acid size, charge, hydropathy indices and matrices for protein structure analysis

Background  

Prediction of protein folding and specific interactions from only the sequence (ab initio) is a major challenge in bioinformatics. It is believed that such prediction will prove possible if Anfinsen's thermodynamic principle is correct for all kinds of proteins, and all the information necessary to form a concrete 3D structure is indeed present in the sequence.     

Corticotropin releasing hormone and its function in the skin.

The skin, as the largest organ of the body, is strategically located as a barrier between the external and internal environments, being permanently exposed to noxious stressors such as bursts of radiation (solar, thermal), mechanical energy, or chemical and biological insults. Because of its functional domains and structural diversity, the skin must have a constitutive mechanism for dealing with the stressors. Activities of the skin are mostly regulated by local cutaneous factors and stressed skin can generate signals to produce rapid (neural) or slow (humoral) responses to local or systemic levels. Thus, the skin neuroendocrine system is comprised of locally produced neuroendocrine mediators that interact with corresponding specific receptors through para- or autocrine mechanisms. Furthermore, it is known for several years that the corticotropin-releasing hormone (CRH)/ pro-opiomelanocorticotropin (POMC) skin system fulfils analogous functions to the hypothalamic-pituitary-adrenal (HPA) stress axis. Additionally, skin cells produce hormones, neurotansmitters and neuropeptides, having the corresponding receptors and the skin itself is able to fulfill a multidirectional communication between endocrine, immune and central nervous systems as well as other internal organs. In summary, the skin expresses an equivalent of the prominent hypothalamic-pituitary-adrenal stress axis that may act as a cutaneous defense system, operating as a coordinator and executor of local responses to stress, in addition to its normal function: the preservation of body homeostasis.     

The current status of the small subunit rRNA phylogeny of the coccidia (Sporozoa)

There is no current comprehensive assessment of the molecular phylogeny of the coccidia, as all recently published papers either deal with subsets of the taxa or sequence data, or provide non-robust analyses. Here, we present a comprehensive and consistent phylogenetic analysis of the available data for the small-subunit ribosomal RNA gene sequence, including a number of taxa not previously studied, based on a Bayesian tree-building analysis and the covariotide model of evolution. The assumptions of the analysis have been rigorously tested, and the benefits and limitations highlighted. Our results provide support for a number of prior conclusions, including the monophyly of the families Sarcocystidae (cyst-forming coccidia) and Eimeriidae (oocyst-forming coccidia), but with bird-host Isospora species in the Eimeriidae and mammal-host species in the Sarcocystidae. However, it is clear that a number of previously reported relationships are dependent on the evolutionary model chosen, such as the placements of Goussia janae, Lankesterella minimia and Caryospora bigenetica. Our results also confirm the monophyly of the subfamilies Toxoplasmatinae and Sarcocystinae, but only some of the previously reported groups within these subfamilies are supported by our analysis. Similarly, only some of the previously reported groups within the Eimeriidae are supported by our analysis, and the genus Eimeria is clearly paraphyletic. There are unambiguous patterns of host-parasite relationship within the coccidia, as most of the well-supported groups have a consistent and restricted range of hosts, with the exception of the Toxoplasmatinae. Furthermore, the previously reported groups for which we found no support all have a diverse range of unrelated hosts, confirming that these are unlikely to be natural groups. The most interesting unaddressed questions may relate to Isospora, which has the fewest available sequences and host-parasite relationships apparently not as straightforward as elsewhere within the suborder.     

The systems biology markup language (SBML): a medium for representation and exchange of biochemical network models

MOTIVATION: Molecular biotechnology now makes it possible to build elaborate systems models, but the systems biology community needs information standards if models are to be shared, evaluated and developed cooperatively. RESULTS: We summarize the Systems Biology Markup Language (SBML) Level 1, a free, open, XML-based format for representing biochemical reaction networks. SBML is a software-independent language for describing models common to research in many areas of computational biology, including cell signaling pathways, metabolic pathways, gene regulation, and others. AVAILABILITY: The specification of SBML Level 1 is freely available from http://www.sbml.org/     

Thrombospondin 2 inhibits microvascular endothelial cell proliferation by a caspase-independent mechanism

The matricellular protein thrombospondin 2 (TSP2) regulates a variety of cell-matrix interactions. A prominent feature of TSP2-null mice is increased microvascular density, particularly in connective tissues synthesized after injury. We investigated the cellular basis for the regulation of angiogenesis by TSP2 in cultures of murine and human fibroblasts and endothelial cells. Fibroblasts isolated from murine and human dermis synthesize TSP2 mRNA and secrete significant amounts of immunoreactive TSP2, whereas endothelial cells from mouse lung and human dermis did not synthesize TSP2 mRNA or protein. Recombinant mouse TSP2 inhibited growth of human microvascular endothelial cells (HMVECs) mediated by basic fibroblast growth factor, insulin-like growth factor-1, epidermal growth factor, and vascular endothelial growth factor (VEGF). HMVECs exposed to TSP2 in the presence of these growth factors had a decreased proportion of cells in S and G2/M phases. HMVECs cultured with a combination of basic fibroblast growth factor, insulin-like growth factor-1, and epidermal growth factor displayed an increased proportion of nonviable cells in the presence of TSP2, but the addition of VEGF blocked this TSP2-mediated impairment of cell viability. TSP2-mediated inhibition of DNA synthesis by HMVECs in the presence of VEGF was not affected by the broad-spectrum caspase inhibitor zVAD-fmk. Similar findings were obtained with TSP1. Taken together, these observations indicate that either TSP2 or TSP1 can inhibit HMVEC proliferation by inhibition of cell cycle progression and induction of cell death, but the mechanisms responsible for TSP2-mediated inhibition of cell cycle progression are independent from those leading to cell death.     

Differential binding of lectins IL-2 and CSL to candida albicans and cancer cells

The demonstration that interleukin 2 (IL-2) is a lectin specific for oligomannosides allows to understand a new function for this cytokine: as a bifunctional molecule when bound to its receptor ss, IL-2 associates the latter which the CD3/TCR complex, interacting with oligosaccharides of CD3 through its carbohydrate-recognition domain (Zanetta et al. , 1996, Biochem. J., 318, 49-53). This induces the tyrosine phosphorylation of the IL-2R beta by ++p56(lck) , the first step of the IL-2-dependent signaling. Since this specific association is disrupted in vitro by oligomannosides with five and six mannose residues, we made the hypothesis that pathogenic cells or microorganisms could bind IL-2, consequently disturbing the IL-2- dependent response. This study shows that the pathogenic yeast Candida albicans (in contrast with nonpathogenic yeasts) binds high amounts of IL-2 as did cancer cells. In contrast with cancer cells, yeasts do not bind the Man6GlcNAc2-specific lectin CSL, an endogenous "amplifier of activation signals" (Zanetta et al. , 1995, Biochem. J., 311, 629-636).      

Characterization of a type IV procollagen synthesized by human amniotic fluid cells in culture.

Fetal epithelioid cells, isolated from human amniotic fluid, synthesize and secrete a type IV-like procollagen characterized by a unique pattern of cyanogen bromide (CNBr)-produced peptides. The procollagen is disulfide-bonded and, after reduction, migrates on sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a doublet between collagen beta components and pro-alpha 1(I) chains. No conversion of the procollagen to collagen or to procollagen intermediates is observed in cell culture. The procollagen was purified by salt fractionation and ion exchange chromatography; its amino acid composition resembles that of collagenous proteins extracted from basement membranes, with a high 3- and 4-hydroxyproline and hydroxylysine content and low levels of alanine and arginine. The major products obtained after limited proteolytic digestion of the protein retain interchain disulfide bonds and, after reduction, migrate on sodium dodecyl sulfate-polyacrylamide gel electrophoresis near intact pro-alpha 1(I) chains. The procollagen is secreted efficiently by amniotic fluid cells despite almost complete inhibition of peptidyl hydroxylation but, unlike type I procollagen, the secreted underhydroxylated chains lack interchain disulfide bonds. Since these cells also secrete fibronectin and elaborate an extensive extracellular matrix, the system should prove useful in the study of cell-matrix interactions.